Request is made for funds to purchase a gas chromatograph/mass spectrometer to serve as the core of a Mass Spectrometry Center at the St. Luke's-Roosevelt Hospital Center (StL-RHC). This Hospital Center, and affiliate of Columbia University has some 80 scientific investigators engaged in various aspects of biomedical research. Five principal users of this spectrometry center can be identified now. With the anticipated growth of the research activities at StL-RHC it is expected that the number of scientists who will find that this instrument can enhance the progress of their research will increase. The presently identified areas of biomedicine that will be serviced by this mass spectrometer are: 1) Studies of some aspect of steroid biochemistry (included here are investigations into a) the biochemistry of the fatty acid esters of steroids, such as pregnenolone and dehydroisoandrosterone; b) the biochemistry of newly discovered sulfolipids of sterols and steroids and c) the occurrence and metabolism of the steroids (such as pregnenolone) recently found in brain tissue. 2) Studies relevant to the treatment and cure of AIDS (included here are) a) analyses required for the study of the pharmacokinetics and the metabolic fates of various drugs (such as Suramin and Ribovirin, etc) which are currently used in the treatment of this disease, b) analyses required during the efforts to synthesize and evaluate new drugs that may be antiviral agents and c) structural analyses required to determine the chemical changes induced in various carcinogens by incubation with viruses. 3) Studies relevant to determine the cause and cure to obesity (included here are various metabolic studies using isotopically labeled cell constituents (H218/O, 13C-leucine, 13C-glucose, etc) to define metabolic abnormalities in morbidly obese humans. 4) Studies on the biochemistry of elastin and its relation to some pathological states of the human lung (included here are structural analyses of the molecules that are cross-links between the protein chains of elastin) and 5) Studies on the biochemistry of the steroidal intermediates in the biosynthesis of cholesterol from lanosterol.